Minecart With TNT blow up obsidian

What I expected to happen was...:
I maked an new type nuke with activator rails and hoped it work like an missile

What actually happened was...:
It stopped in the air and blow extra strong and exploded Infiniti times

Steps to Reproduce:
1. Make an nucke station in the air set 3 rails 2 normal and 1 activator rail like an L
2. Place a lot of minecart with TNT on the midle rail
3. activator the Activator rail and send the minecart with TNT into the air